Which of the following indicates that an exothermic reaction has taken place?
2 answers:
Answer: Option (B) is the correct answer.
Explanation:
An exothermic reaction is defined as the chemical reaction in which there occurs release of heat.
For example,
In an exothermic reaction, energy of reactants is more than the energy of products.
Whereas an endothermic reaction is defined as a chemical reaction in which heat is absorbed by reactant molecules.
For example,
In endothermic reaction, energy of reactant molecules is less than the energy of products.
Thus, we can conclude that release of heat and/or light energy indicates that an exothermic reaction has taken place.
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The question is incomplete, so I tried to find a similar problem online. It is shown in the attached picture. The reaction is
PCl₃ + Cl₂ ⇆ PCl₅
Then, we use the ICE (Initial-Change-Excess) approach as follows:
PCl₃ + Cl₂ ⇆ PCl₅
I 0.5 0.5 0.3
C -x -x +x
E 0.5-x 0.5-x 0.3+x
Total pressure: 0.5 - x + 0.5 - x + 0.3 + x = 1.3
Kp = [PCl₅]/[PCl₃][Cl₂]
0.18 = (0.3+x)/(0.5-x)²
Solving for x,
x= 0.21
Partial pressures would be:
<em>PCl₃ = 0.5 - 0.21 = 0.29 atm</em>
<em>Cl₂ = 0.5 - 0.21 = 0.29 atm</em>
<em>PCl₅ = 0.3+0.21 = 0.51 atm</em>
PCl₃ + Cl₂ ⇆ PCl₅
Then, we use the ICE (Initial-Change-Excess) approach as follows:
PCl₃ + Cl₂ ⇆ PCl₅
I 0.5 0.5 0.3
C -x -x +x
E 0.5-x 0.5-x 0.3+x
Total pressure: 0.5 - x + 0.5 - x + 0.3 + x = 1.3
Kp = [PCl₅]/[PCl₃][Cl₂]
0.18 = (0.3+x)/(0.5-x)²
Solving for x,
x= 0.21
Partial pressures would be:
<em>PCl₃ = 0.5 - 0.21 = 0.29 atm</em>
<em>Cl₂ = 0.5 - 0.21 = 0.29 atm</em>
<em>PCl₅ = 0.3+0.21 = 0.51 atm</em>